WASHINGTON — The Pentagon scored an important success Tuesday in a test of its oft-criticized missile defense program, destroying a mock warhead over the Pacific Ocean with an interceptor that is key to protecting U.S. territory from a North Korean attack.

This was the first test against a missile traveling at the trajectory and speed of an intercontinental ballistic missile — a weapon which could threaten the U.S. mainland with a nuclear warhead.

North Korea continues developing shorter range missiles and its leader, Kim Jong Un, has announced he intends to launch an ICBM sometime this year, CBS News’ national security correspondent David Martin reports.